Gallery: Tablet Computing From 1888 to 2010

The word “tablet” used to refer to a flat slab for bearing an inscription. Leave it to the tech industry to make it into something far more complicated and confusing.

Scores of products marketed as “tablets” have come and gone, and now — with rumors of imminent tablet computers from Apple, Dell, Microsoft and others — the category seems ripe for a rebound.

“If people can figure out a new device category that consumers will want to buy that isn’t a laptop or a phone, that opens a whole new possibility in markets to conquer,” explains Michael Gartenberg, a tech strategist with Interpret. “That’s why companies continue to invest in this space, and we have a large number of bodies that are littered in this space.”

Let’s take a look at tablets past, present and future. If the upcoming tablets are to succeed, they’ll need to learn from hideous mistakes like the Apple Newton and the Tablet PC.

Origins The origins of the tablet computer can be traced as far back as the 19th century. Electrical engineer Elisha Gray registered an 1888 patent (.pdf) describing an electrical-stylus device for capturing handwriting. Famous for his contributions to the development of the telephone, Gray’s idea with a “tablet” was not for drawing, but rather a method of using telegraph technology to transmit handwritten messages. (Think of it as a primitive form of instant messaging or e-mailing.)

Gray’s concept wasn’t merely a flat slab. His patent depicts two instruments: a transmitter and a receiver. The transmitter is a pen-like device connected to two electric circuits acting as interruptors. Current interruptions are used to translate the transmitter pen’s movements into signals transmitted to the receiver pen to mimic the movements, thereby reproducing the message on a piece of paper.

This description hardly sounds anything like a tablet, but later electronic-handwriting-recognition patents built from the idea of transmitting and receiving instruments, eventually combining them into one slab-shaped device like the tablets we see today.

The Apple Newton
The Newton MessagePad (above) was the first attempt by a major computer company at producing a commercial tablet-type computer for the mass market. Weighing in at about two pounds, Apple’s 1993 foray into tablet computing sported a powerful-for-its-time 20 MHz processor and a pen-centric interface. Writing recognition in the first version was so bad that it was famously mocked in a Doonesbury cartoon, and though it subsequently improved, the Newton never recovered from the initial PR blow. In 1998, Apple discontinued the Newton when Steve Jobs retook the helm as CEO, leaving a small coterie of true believers to keep the product’s memory alive.

PDAs and Smartphones
While no one refers to their iPhone as a “pocket tablet,” these devices are an important stage in the development of tablet computers.

Palm founder Jeff Hawkins learned from Apple’s mistakes and set out to build a pocket-sized computer that was smaller, cheaper, more modest in its ambitions and ultimately more useful than the Newton. He succeeded wildly with the 1996 launch of the Palm Pilot, spawning a long line of pen-based personal digital assistants from Palm, HP, Dell and others.

When Apple returned to the touchscreen world with the iPhone in 2007, it showed that it had paid close attention during the decade since the Newton flopped. The iPhone was simple, small, elegant and did a handful of things — make calls, browse the web, handle e-mail — very well. The fact that it wasn’t an all-purpose portable computer didn’t seem to matter so much compared to its usability and design.

Graphics tablets

Graphics tablets are computer input devices with a stylus-controlled interface. The technologies used vary, but generally all graphic tablets use the received signal to determine the horizontal and vertical position of the stylus, distance of the stylus from tablet surface and the tilt (vertical angle) of the stylus. Popular among digital illustrators, tablets facilitate a natural way to create computer graphics, especially 2-D illustrations.

Given their specialty, graphics tablets fill a niche for digital artists. Some consumer applications include writing Chinese, Japanese or Korean characters, working with handwriting recognition software to transfer them onto the computer. The stylus can also be used as a mouse.

However, for other languages, including English, the majority of consumers prefer typing on a keyboard for speedier writing, according to Gartenberg. Thus, the graphics tablet fills a niche in the design industry, but it is not a major product category in the consumer market. Wacom is the most prominent manufacturer producing graphics tablets today. (Example above: Wacom Bamboo Fun)

Tablet PC
The Tablet PC is a portable computer equipped with a touchscreen for interaction with a stylus or finger gestures. Microsoft cooked up the specification in 2001, and released several versions of Windows made to work with compatible computers, adding support for things like pen-based navigation and digital ink capture. The Tablet PC comes in a variety of flavors: Slates, convertibles and hybrids.

“Slate” tablet PCs are slabs containing the guts of a computer with a touchscreen as a dedicated display. Slate tablets are keyboardless, and almost all input happens via the touchscreen. An external keyboard or mouse can be attached via USB or wireless. Slates vary depending on the type of touchscreen used (more on that later). (Example: Axiotron Modbook)

Another type of tablet PC is the convertible notebook, which is basically a keyboard-equipped notebook featuring a swivel touchscreen. The touchscreen can be opened to take on the clamshell form of a notebook for use with a keyboard and mouse. Or, you can rotate the touchscreen backward and fold it down to turn the computer into a flat, slate-like surface to write on. This design is fundamentally flawed, as it creates a point of physical weakness on the device. (Example (right): Asus EeePC T101H)

Finally, hybrids are essentially convertible tablets with removable keyboard, allowing you to use them as slabs. (Example: HP Compaq TC1000)

The Tablet PC concept has been driven primarily by Microsoft, which created a special version of Windows XP to support tablet functions like pen sensing and digital ink, then worked with manufacturers to set minimum specifications. As a product category, Tablet PCs never proved all that popular with consumers, however. Why spend an extra $500 to get a computer with a few extra features and a display that is less clear, thanks to the added layer of touch- or stylus-sensing electronics?

Touchscreen Tech
Before we move to the tablets of tomorrow, let’s take a detour to explain the two primary touchscreen technologies: resistive and projected capacitive touch.

Resistive touchscreens contain metallic, electrically conductive layers. Pressing down on a point on the panel’s outer surface causes the layers to connect at a point; the change in electrical current communicates the action to the computer. Resistive touchscreens are the most affordable touchscreens, thus they were the most prevalently used technology for several years. On the down side, they suffer from low durability and poor transmissivity, according to Jennifer Holgrove, director of display technologies at DisplaySearch, a market research firm.

Newer, projected capacitive touchscreens are quickly becoming popular. In projected capacitive touchscreens, the conductive layer is etched into the screen, which translates into higher accuracy and more flexibility (compared to sensing detection through multiple layers). Electrodes sense a user’s fingers on the X and Y axes, negating the need for a stylus. However, a stylus can still be used for more accurate pointing. The grid composition enables higher resolution, and multitouch is possible (i.e., the ability to detect multiple inputs simultaneously).

Guess which popular device uses a projected capacitive touchscreen? That’s right, the iPhone — which brings us to the topic of future tablet devices.

Tablets
When journalists and Apple fanatics started jabbering about a rumored Apple tablet, the word “PC” was dropped from the dialogue. That’s probably because when the words “Apple” and “PC” are placed near one another, it makes nerds sweat. Plus, “Apple tablet PC” doesn’t have a very good ring to it, does it? Say what you will, but an Apple tablet — in so far as it has been described in rumor reports — would still be a personal computer.

The Apple tablet hasn’t even been confirmed to exist, and already it has already entered the social consciousness of the tech world to create a potential new category. In anticipation of Apple delivering a tablet, rivals are preparing their own tablet devices. Sources have told Wired.com that Dell, Intel, HTC and Nokia are developing tablets for release next year. Analysts and various media outlets have heard rumors about tablets ranging from 5 to 10 inches. Archos has been quick to show off what it calls a tablet — a 9-inch touchscreen device running Windows 7. TechCrunch’s Michael Arrington is also rushing to release a tablet called the CrunchPad.

What differentiates a tablet from a tablet PC? Not much, but it appears tablets (from what we’ve seen) feature multitouch, rendering Tablet PCs with those yucky resistive touchscreens passé.

But does that make the iPhone, the iPod Touch, or Microsoft’s table-shaped Surface all tablets? Probably not. So here is what appears to be the collective definition of a tablet: